The great Norwegian crime novelist Karin Fossum has a special gift for voices. She’s come up with a humdinger in the first-person narrator of “I Can See in the Dark”:

“Everyone has virtues, everyone has a talent, everyone has a right to respect,” says a courteous, cunning psychopath named Riktor. “That’s how we human beings like to think. But rotten individuals do exist and, I have to admit, I’m one of them: a rotten individual who in certain situations can turn spiteful, to the extent that I become almost unhinged. But I find no difficulty in aping other people, aping politeness and friendliness and kindness. It’s restraining the bad impulses that’s tough. I often think of the things that might happen if I really lost control, and that does happen from time to time.”

And how is well-mannered, deranged Riktor employed? As a caregiver and dispenser of medications in a nursing home. Fossum once worked in one, and she brings a sympathetic understanding of elderly nursing-home inmates’ vulnerabilities. This is a nightmarish tale of our worst fears of how we or our parents or spouses could conceivably end up.

Riktor, a loner in his 40s, is known around the Lokka nursing home as a bit of an oddball — childhood schoolmates mocked him for looking like a pike — but reliable enough and with a warm smile always at the ready. Head nurse Anna Otterlei, his supervisor, is unaware that the sexually inexperienced Riktor often fantasizes about fondling her. Nor does she know that he stealthily tortures the patients under his care. Those who for physical or mental reasons are unable to speak are easy marks. Old, blind Nelly is a favorite victim. Riktor pulls her hair and pinches the flesh behind her ear until she writhes. Instead of injecting Nelly and other patients with the drugs prescribed by Dr. Fischer, Lokka’s medical director, Riktor pumps the painkillers and other medications into patients’ mattresses. He flushes pills and food down the toilet. Dr. Fischer, a bit slow on the uptake, doesn’t understand why so many patients hurt all the time or are emaciated.

Although Riktor accepts that he is “an evil little devil,” he struggles constantly to rationalize his behavior. Why should he medicate or feed his patients, he asks himself, when “they’re on the brink of death and are unproductive and useless now, and don’t even afford anyone any pleasure?” Anyway, “what’s the point in eating when you’re almost a hundred?”

"I Can See in the Dark" by Karin Fossum (Houghton Mifflin Harcourt | Handout image)

Spending 210 suspenseful pages inside Riktor’s terrifying head is made possible for non-sadistic readers by the occasional traces of humanity Fossum endows him with. Riktor spends many of his off-hours on a bench in a lakeside park along with other troubled or forlorn villagers. It’s there that he experiences actual guilt when he fails to report watching a skier plunge through the ice, thrash about and sink beneath the surface. He also develops tender feelings for another park regular, an alcoholic who accompanies Riktor home a few times for free booze. “I felt happy, standing there on the steps,” Riktor says, surprised by his feelings. “I liked this new condition of having a friend.”

While Fossum’s Inspector Konrad Sejer does not appear in “I Can See in the Dark,” another entertaining cop does. An amusingly puffed-up detective named Randers knocks on Riktor’s door after Nelly is discovered smothered with a pillow. Randers wrongly suspects Riktor in the old lady’s death — although not in the disappearance of one of the lakeside park’s denizens, who in fact is buried in Riktor’s back yard. This is a juicy — if not all that original — twist, and suddenly a desperate, enraged Riktor is beside himself. He’s convinced that “someone was making a fool of me.”

Eventually, a measure of justice is done, and when the identity of Nelly’s killer is revealed, it’s wrenching. It is Riktor, though, whom we end up fearing might be out there somewhere, waiting. He’s no Hannibal Lecter; there’s no brain-gobbling here. But Riktor is even scarier because he seems so much more likely to turn up in real life with his distinctive turn of mind. He has trouble burying the body of someone he’s bludgeoned to death because, he explains, “I’d never had much of a physique; the intellect was more my métier.”

Richard Lipez writes the Don Strachey detective novels under the name Richard Stevenson.

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Comments our editors find particularly useful or relevant are displayed in Top Comments, as are comments by users with these badges: . Replies to those posts appear here, as well as posts by staff writers.